The present invention relates to a ceramic structure obtained by combining to integrate a plurality of sintered ceramic material segments.
When a ceramic structure of large thermal expansion is disposed and used in a site such as an exhaust gas passage that undergoes thermal impact, it is feared that cracks may be formed by the thermal impact. In order to solve this problem, there is disclosed in, for example, JP-A-8-28246, a technique of, as shown in FIG. 3, constituting a ceramic structure with a plurality of segments 3 and interposing an elastic sealing material or the like between the segments 3 to release the thermal impact received.
The thermal impact-relieving zones 5 formed by interposing the sealing agent or the like between the segments 3 are preferred to be as wide as possible in the sectional direction of the ceramic structure, from the standpoint of thermal impact relief. However, as the width W of the thermal impact-relieving zones is larger, the effective sectional area of the ceramic structure used for intended purpose is smaller correspondingly, resulting in reductions in the overall properties and efficiency of the structure and further in the overall strength of the structure. Meanwhile, when the width W of the thermal impact-relieving zones 5 is designed at a small level, the thermal impact received is difficult to release sufficiently and the thermal impact-relieving zones 5 themselves or the segments 3 are impaired.
The width W of the thermal impact-relieving zones is set preferably at an appropriate level so as to balance the above-mentioned parameters contradictory to each other. Balancing the two parameters actually, however, is difficult and the level of the thermal impact received differs depending upon the material of the segments 3, the material of the sealing agent or the like interposed between the thermal impact-relieving zones, and the application of the ceramic structure; therefore, there has been a problem that even if the width W of the thermal impact-relieving zones has been optimized, its practical applicability is very low.
The present invention has been completed in view of the above-mentioned situation, and aims at providing a ceramic structure which can release the received thermal impact sufficiently without significantly reducing the effective sectional area of the ceramic structure and the overall strength of the structure and which is abound in the universality in materials and applications as a ceramic structure.
According to the present invention, there is provided a ceramic structure obtained by combining a plurality of sintered ceramic material segments having a thermal expansion coefficient of 3.0xc3x9710xe2x88x926/xc2x0 C. or more and integrating them, characterized in that ceramic structure thermal impact-relieving zones capable of releasing the thermal impact applied are provided between the segments, and that the thermal impact-relieving zones in the sectional direction of the ceramic structure have the diversity in the width.